The building sector accounts for a significant proportion of global carbon emissions, making it a critical area for achieving carbon neutrality and sustainable development. This study addresses the limitations of existing carbon accounting methodologies by developing a Comprehensive Life-cycle Carbon Accounting Model and a Green Building Evaluation Framework and Monitoring System. The proposed model integrates life-cycle assessment (LCA) principles with electricity big data to accurately quantify carbon emissions across all building life-cycle stages-material production, construction, operation, and decommissioning. By leveraging real-time energy consumption data, the model enhances precision and provides actionable insights for emission reduction strategies. The Green Building Evaluation Framework complements this model by incorporating sustainability metrics such as energy efficiency, material usage, and environmental impact. These metrics are operationalized through a modular monitoring system based on a microservice architecture, enabling real-time data collection, analysis, and visualization. This system facilitates green certification, policy formulation, and decision-making for developers, regulators, and policymakers. This research provides a robust foundation for advancing green building practices, aligning with global carbon neutrality goals, and supporting broader adoption of data-driven sustainability initiatives.